1111 CRAFTSMAN WAY 2016-01-01 MF Import

is estimated that thc avcrage recu�rence interval for interface earthquakes on thc Cascadia Subduction 7_ane is about 400 to G00 years; however,thc intcrvai between earthquakes is irrcgular. ICascadia Subduction 2one Intraplate Earthquakes. Cascadia Subduction Zone intraplate earthquakes occur within the subducting Juan de Fuca Plate at depths of 30 to 40 miles within westem �Vashingron. ]ntraplate carthquakes arc expected to have durations ranging up to 45 seconds and maSmitudes ranging up ro 7.5. The Olympia 1949 (ma6mimdc 7.I), the Scattle 196� (mabmitude G.5), and the Nisqually 200i (magnitude 6.8)are considered to be ir.traplate earthquakes. Site Coe�cients Wc rccommend the project sitc bc classificd as Site Class G as defined in the 2006 Intemational Building Code. Recommended spectral response accelerations are providcd below. Spectrel Response Accelerations in Accordance with 2006 IBC (SRA)and Site CoeHiciants ShoR Period t Second Periad Mapped SRA Ss= 1.15 Si =0.40 Site Cae(ficieMs F,=0.9 F.=2.4 Max.Considered Earthquake SRA Sn�=1.04 Su, =0.96 Design SRA Sos=0.69 Soi =0.64 INote: Sile Class E Description:Soft Soil Profile iLiquefaction Potential Liquefaction refers ro a condition wherc vibration or shaking of the ground, usually from carthquake I forces, results in thc de��elopment of excess porc pressures in saturated soils and subsequent loss of strength. This can result in vertical oscillations and/or lateral sprcading of the aCfectcd soils ��ith accompanying surface subsidenee and/or heaeing. In general, soils, which are susceptible to liyuefaction, include luosc to medium dense cican to siity sands which are saturated (i.e.,below the water table). Portions of thc soils encountcred bclow thc watcr table are susceptible to liquefaction during a modcrate to large carthquake. �Ve estimate that 2 ro G inches of ground settlemcnt can occur during the design carthquakc (magnitude 7.5). Because of the eariabiliry of the consistcncy and fines content in the subsurface deposits, the magnitude of liquefaction-induced differcntial set4emcnt may approach the total estim�ted sctdement. i Other Consideretions Becausc of the presence of ��cry loosc silty sand and sott silt bencath thc building footprint, wc recommend that the foundation be tied together to offer protection abainst minor earthquake shaking. �Ve understand that this will be accomplished by using a �erimeter grade beam footing and rying the floor sl�b and interior column footings togcth�r. hYlr Na. /165_'-001�00 PagC 7 GEOENGINEEP� �1'ocrmLrr G,?006